Press



R.A scHULTE E'r AL PRESS Filed Nov. a, 1957 R. SCHULTE ET AL PRESS 5 Sheets-Shen 8 Aug. 25, 1970 Filed Nov. a. 1967 Aug. Z5, 1970 R. scHuL'rE ET Al.

' PRESS Filed Nov. 8, 1967 5 Sheets-Sheet 3 Aug. 25. w70

Filed Nov'. 8, 1967 R SCHULTE ET L PRESS 5 Sheets-Sheet 4,

Aug. 25, '1970 R. ssa-suma ETAI- 3,525,243

lmams Filed Nov. 8, 1967 5 Sheets-Sheet 5 MA1-w51.

United States Patent O' Inf. ci. Bzid 43/10 U.S. Cl. 72-361 17 Claims ABSTRACT F THE DISCLOSURE A press with a row of progressive dies wherein the 'workpieces are partially expelled from dies by ejector pins and the thus exposed portions of workpieces are thereupon grasped by the claws of grippers which are movable axially of the dies to fully extract the workpieces and also transversely back and forth to move fully extracted workpieces from registry with preceding dies into registry with the next-following dies. Each gripper and the jaws of each gripper are movable independently of the other gripper or grippers. The press is particularly suited for the production of metallic workpieces whose diameter is a small fraction of their axial length.

The grippers may be disposed at one or both sides of the row of dies and are movable radially of the dies, either at right angles to the common plane of the axes of dies or at an acute angle to such plane.

BACKGROUND OF THE INVENTION The present invention relates to presses in general, and more particularly to improvement in presses wherein the workpieces are treated in stages at several successive stations. Still more particularly, the invention relates to improvements in presses for elongated workpieces of the type having a length which is a multiple of the diameter.

In certain presently known gang presses for elongated workpieces, the blanks are inserted by hand into the rst of a series of progressive dies. The dies cooperate with male deforming members or punches which deform the blanks or partially finished workpieces therein and with ejector pins or knockout pins which are arranged to expel the workpieces from the respective dies subsequent to retraction of the punches. The attendants intercept the ejected workpieces with tongs and insert the thus intercepted workpieces into the next following dies or transfer them onto a takeoff conveyor or into a collecting receptacle. Such Work is tiresome, particularly if the workpieces and blanks are heavy. Furthermore, the Work 0f attendants is dangerous, particularly if the workpieces are hot.

It is also known to equip a press wherein the workpieces are treated successively from station to station. Such transfer mechanisms are often employed in presses for the manufacture of bolts, nuts or similar lightweight articles. As a rule, the grippers of the transfer mechanism are held in closed position by springs and open up to engage the workpieces in response to pressure transmitted by workpieces on explusion from the dies by the ejector pms.

In certain other conventional presses, particularly for the production of relatively short workpieces with a large diameter, the workpieces are completely ejected from the cavities of dies and are held by ejector pins in a transfer plane. The work-engaging jaws of the grippers are moved apart and the grippers are then shifted into engagement with the workpieces in the transfer plane prior to closing of the jaws. In the next step, the grippers are moved from a preceding die into registry with the next P ICC following die and the jaws are opened again to permit entry of workpieces into the cavities of registering dies.

The above described conventional presses with automatic transfer mechanisms are unsatisfactory for the production of relatively long workpieces, and they are even less satisfactory for the production of workpieces whose diameter changes in the axial direction thereof. For example, it is often necessary to form spindles, shafts, axles or similar elongated articles with several axially spaced shoulders, collars, flanges or the like. Such workpieces cannot be manipulated by presently known transfer mechanisms, especially if the grippers close in response to spring bias because the bias would have to be adjusted in dependency on the diameter of that portion of a workpiece which is to be gripped during transport. Moreover, it is very difficult to maintain such elongated workpieces in requisite position subsequent to complete ejection from the cavities of dies and prior to satisfactory engagement by the grippers. Even if the operation of ejectors is fully synchronized with the operation of grippers, the workpieces are likely to tilt or to fall out of the gripper jaws, especially if the worpieces are rather heavy and long. It is often necessary to press-form workpieces whose length is in the range or in excess of 300 millimeters.

SUMMARY OF THE. INVENTION It is an object of our invention to provide a press wherein elongated workpieces are shaped in a series of progressive dies with a novel and improved transfer mechanism which can safetly transport blanks to the first or foremost die, which can transport partially finished workpieces from preceding to next-following dies, and which can also transfer finished workpieces from the last die to a takeoff conveyor or the like.

Another object of the invention is to provide a transfer mechanism for gang presses which occupies little room, which can be readily converted for transfer of longer, shorter, heavier, lighter, smaller-diameter or large-diameter workpieces, and whose operation is fully automatic.

A further object of the invention is to provide a transfer mechanism which can manipulate elongated articles of the type wherein the diameter varies once or more than once in the longitudinal direction thereof.

An additional object of the invention is to provide novel and improved grippers for use in a transfer mechanism of the above outlined character.

A concomitant object of the invention is to provide the transfer mechanism with novel and improved means for moving the grippers with as Well as relative to each other.

An ancillary object of the invention is to provide a gang press which is particularly suited for the mass production of complicated elongated metallic workpieces.

The improved press comprises a frame having a table for a succession or row of progressive work-receiving dies and two upright columns for a crosshead which supports male deforming members cooperating with the dies to shape the workpieces which are received in the cavities of the dies. The transfer mechanism serves to transport workpieces to and from the dies and comprises ejector means each movable with reference to one of the dies to expel a portion of a workpiece therefrom, grippers movable into and from clamping engagement with the thus exposed portions of workpieces, and means for moving the grippers axially of the dies to fully Withdraw a workpiece whose exposed portion is clamped by a gripper or to introduce into a die a workpiece whose exposed portion is clamped by a gripper. The transfer mechanism further comprises means for moving the grippers back and forth in parallelism with the row of progressive dies through distances corresponding to the spacing of the dies from each other.

The means for moving the grippers axially of the dies preferably comprises one or more carriages on which the grippers are movable independently of each other, ways supporting the carriages for movement in the longitudinal direction of the row of dies, and lifting means for moving the ways axially of the dies.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved press itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusual of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a horizontal sectional view of a press which embodies one form of our invention and wherein all the grippers are mounted on a single carriage;

FIG. 2 is a similar horizontal sectional view of a second press wherein the grippers are mounted on separate carriages at both sides of a row of progressive dies;

FIG. 3 is a fragmentary vertical sectional view, substantially as seen in the direction of arrows from the line III-III of FIG. 2;

FIG. 4 is a slightly enlarged fragmentary partly sectional detail view of the structure shown in FIG. 3;

FIG. 5 is a section as seen in the direction of arrows from the line V-V of FIG. 4;

FIG. 6 is an enlarged fragmentary top plan view of a gripper;

FIG. 7 is an enlarged fragmentary vertical sectional view as seen in the direction of arrows from the line VII--VII of FIG. 1 but with the gripper omitted;

FIG. 8 is a similar sectional view but showing another stage in the treatment of a workpiece in the cavity of the first die;

FIG. 9 is a similar view but showing a third stage when the exposed portion of a workpiece is grasped by the jaws of a gripper; and

FIG. 10 illustrates a fourth stage when the workpiece is fully extracted from the cavity of the die.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a horizontal sectional view of a press which comprises a frame including a table or support 1b for a row of three progressive dies 29a, 29b, 29C. Two upright columns 1, 1a of the frame flank the table 1b and support a customary crosshead (not shown) for the male deforming members or punches which are movable up and down to deform blanks which are supplied by a feed 26 to the cavity of the first or leftmost dies 29a. The belt of the takeoff conveyor for finished workpieces is shown at 31. This belt is driven by an electric motor 31a.

The transfer mechanism for transporting blanks and workpieces from the feed 26 to the first die 29a, from the die 29a to the die 29h, from the die 29h to the die 29r,` and from the die 29C to the belt 31 comprises three ejector pins or knockout pins (not shown in FIG. 1) which are coaxial with and are mounted for vertical movement below the dies 29a, 29b, 29e, and four grippers 3, 4, S, 6 which are provided with jaws or claws movable between open and closed positions. The grippers 3 to 6 respectively serve to transport blanks from the feed 26 to the first die 29a, to transport partly finished workpieces from the die 29a to the die 29b, to transport partly finished workpieces from the die 29h to the die 29C, and to transport finished workpieces from the die 29C to the belt 31. The function of the aforementioned ejector pins is to partially lift the workpieces from the cavities of the dies 29a, 2912, 29C so that the workpieces can be readily engaged by the jaws of the grippers 4 to 6. The grippers 3-6 are mounted on a slide or carriage 7 which is supported by ways 10 and is reciprocable by a hydraulic or pneumatic cylinderassembly 7a adapted to move the slide in parallelism with the common plane of the axes of dies 29u, 29h, 29e. The grippers 3-6 are normal to the ways 10 and are movable radially of the dies, i.e., at right angles to the common plane of the axes of the three dies. The operation of ejector pins is synchronized with operation of punches which are movable up and down with the crosshead. When the punches move upwardly, the ejector pins lift the top portions Of the workpieces to a certain level above the respective dies so that the grippers 4-6 are then free to move from their retracted positions (indicated by phantom lines) to forward or operative positions (indicated by solid lines) and to grip the thus exposed top portions of workpieces for transfer to the next-following dies and to the belt 31. Since the ejector pins lift the workpieces only partially above the dies 29a-29c, the grippers 4-6 must perform vertical reciprocatory movements in order to lift the workpieces completely above the dies prior to movement with the slide 7 in the longitudinal direction of the ways 10, i.e., in a direction to the right, as viewed in FIG. 1. This will be described in connection with FIGS. 7 to 10.

FIG. 2 shows a second press whose frame includes a table or support 2b for two progressive dies 30a, 30b and two upright columns 2, 2a for the vertically reciprocable crosshead (not shown) rwhich supports the punches. This press comprises four grippers 3a, 4a, and 5a, 6a which are respectively mounted at opposite sides of the dies 30a, 30]; and are supported on slides or carriages 8, 9. These slides are respectively supported by way 11, 12 which are parallel to each other and to the common vertical plane of the axes of dies 30u., 30h. The grippers 3a-6a make 45- degree angles with the longitudinal directions of the ways 11, 12 to reduce the dimensions of the working station. The means for reciprocating the slides 8, 9 compirse hydraulic or pneumatic cylinder assemblies 8a, 9a mounted on the ways 11, 12. As shown in FIGS. 3-5, the ways 11 are mounted on two guide means which include plungers 13 guided in antifriction bearings 15 provided therefor in fixed cylinders 14 carried by the table 2b. The ways 10 of FIG. 1 and the ways 12 of FIG. 2 are mounted in similar fashion on the table 1b, 2b, respectively. The lifting means for raising and lowering the ways 11 comprises a piston which is installed in a double-acting hydraulic or pneumatic cylinder 16 and has a piston rod 17 articulately coupled to one arm 18a. of a two-armed lever 18 whose other arm 181; is coupled to the ways 11 by a link 19. The ways 10 and 12 can be raised and lowered by cylinders which are identical with the cylinder 16.

The gripper 4a of FIG. 5 is reciprocable with reference to the slide 8 by a double acting cylinder 20 -whose piston rod 21 is coupled to the rear portion of the gripper. The jaws or claws 22, 22a of the gripper 4a are shown in FIG, 6. These jaws are coupled to each other by a pivot pin 22h and are respectively connected with toggle links 24, 24a which are coupled to a push rod 23 by a pin 24h. The push rod 23 is reciprocable in directions indicated by arrow 25. The means for reciprocating the push rod 23 in synchronism with movement of the gripper 4a with reference to the slide 8 and in synchronism with movement of the slide 8 with reference to the ways 11 is not. shown in the drawings. The grippers 3 6, 3a and Sci-6a are operated in similar fashion.

FIG. 3 illustrates certain details of the feed 26 which includes a feed chute 26a. The lower end portion 27 of the chute 26a is pivotable about a horizontal pin 27a by means of a piston rod 28a forming part of a double-acting cylinder 28. When the end portion 27 is pivoted in a clockwise direction, as view in FIG. 3, it moves a blank 40` into the range of the jaws on the gripper 3a. The feed of FIG. 1 is of similar design, i.e., the pivotable end portion of the feed chute in this feed can deliver blanks into the range of the jaws on the leftmost gripper 3. FIG. 3 shows further than the upper stretch of the belt 31 slopes downwardly so that the finished workpieces travel along a donwardly inclined path.

The operation of the press shown in FIG. 1 will be described with reference to FIGS. 7 to 10. FIG. 7 shows a male deformng member or punch 32 in lower end position in which the punch bears against the top part of a workpiece 40a in the cavity of the die 29a of FIG. 1. The ejector pin 33 which is associated 'with the die 29a is shown in the lower end position. This ejector pin is thereupon lifted to assume the position shown in FIG. 8 and to raise the top portion of the workpiece 40a above the top face of the die 29a after the crosshead lifts the punch 32 to the raised position shown in the upper part of FIG. 8. In the next step which is shown in FIG. 9, the jaws of the gripper 4 engage the exposed top portion of the workpiece 40a. and the gripper 4 is caused to move upwardly with the slide 7, as indicated by the arrow, to ultimately assume the fully raised position of FIG. l0. The ejector pin 33 descends to its lower end position as soon as the fworkpiece 40a is properly grasped by the jaws of the gripper 4. The slide 7 is then caused to move in a direction to the right, as viewed in FIG. l, and to place the workpiece 40a into registry with the die 29b. The gripper 4 desconds with the slide 7 and inserts the workpiece 40a into the cavity of the die 29h. In the next step, the gripper `4 is retracted after its jaws open so that the crosshead can descend again and to move the punch which registers with the die 2912 into deforming engagement with the workpiece 40a. The operation of grippers 3, 6, 3a-6a is analogous with the exception that the grippers 3, 3a transfer blanks from the end portion 27 of the chute 26a. to the first die 29a or 30a and that the grippers 6, 6a transfer finished workpieces from the dies 29C, 30th to the belt 31.

The numeral 34 shown in FIGS. 2 and 5 denotes an intermediate die which is needed if the workpieces are finish-pressed in the die 30b.

An important advantage of the improved transfer mechanism is that the ejector pins 33 need not completely expel the workpieces from the respective dies, i.e., that the workpieces are partially exposed but are still supported by the dies prior to satisfactory engagement by the jaws 22, 22a of the grippers. The jaws open automatically when the grippers are shifted toward the dies. The jaws of each gripper can open and close independently of the other grippers, and each gripper can be shifted with reference to the associated slide independently of the other grippers. This brings about the advantage that one or more grippers can be rendered inactive for certain operations which require treatment of workpieces in a series of stages whose combined number is less than the number of progressive dies. Consequently, the wear on the grippers is less than in presently known automatic transfer mechanisms wherein each gripper is always compelled to share the movements of all other grippers, irrespective of whether the treatment is carried out at some or all of the stations.

The embodiment shown in FIG. 2 is preferred when the transfer mechanism comprises a relatively large number of grippers and when the press must be accommodated in a relatively small space. As shown in FIG. 2, the first and last grippers 3a, 6a can extend well into the columns 2, 2a. Therefore, the distance between the columns 2, 2a is less than the distance between the columns 1, 1a of FIG. 1.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A press for elongated workpieces, comprising a frame; a row of progressive work-receiving dies mounted in said frame; male deforming members cooperating with said dies to shape the workpieces which are received therein; and transfer means for transporting the workpieces to and from said dies, comprising elongated grippers movable into and from clamping engagement with the workpieces in said dies, said grippers including at least one first elongated gripper disposed at one side of said row of dies inclined relative to the direction of said row and at least one second elongated gripper disposed opposite said first gripper at the other side of said row of dies and also inclined relative to said row, and independent moving means for moving said elongated grippers in substantial parallelism with said row and independently from each other.

2. A press as defined in claim 1, wherein said transfer means further comprises a plurality of ejector means each movable with reference to one of said dies to expel a portion of a workpiece therefrom, said grippers being Imovable into and from clamping engagement with the thus exposed portions of workpieces, and second moving means for moving said grippers substantially axially of the dies to fully withdraw a workpiece whose exposed portion is clamped by a gripper or to introduce into a die a workpiece whose portion is clamped by a gripper.

3. A press as defined in claim 2, wherein said transfer means further comprises third unoving means for moving said grippers into and from clamping engagement with exposed portions of workpieces independently of each other.

4. A press as defined in claim 2, wherein said second moving means comprises carriage means supporting said grippers, ways for said carriage means, and means for moving said ways axially of said dies.

5. A press as defined in claim 1, wherein said grippers comprise work-engaging jaws and means for moving said jaws between open and closed positions.

6. A press as defined in claim'l, wherein said grippers are movable into and from clamping engagement with exposed portions of workpieces in directions which are substantially normal to said row.

7. A press as defined in claim 1, wherein said grippers are movable into and from clamping engagement with exposed portions of workpieces in directions making an acute angle with said row.

8. A press as defined in claim 2, wherein said second moving means comprises first and second carriages for said first and second grippers, first and second ways for said first and second carriages, and first and second lifting means for moving said first and second ways axially of said dies.

9. A press as defined in claim 8, wherein said grippers are movable into and from clamping engagement with the exposed portions of workpieces in directions making an acute angle with said row of dies.

10. A press as defined in claim 1, wherein said moving means comprises means for moving said grippers lengthwise of said row back and forth through distances corresponding to the spacing of said dies from each other.

11. A press as defined in claim 2, wherein said second moving means comprises carriage means for said grippers, ways for said carriage means, said ways extending in parallelism with said row, and lifting means for moving said ways in the axial direction of said dies, said first mentioned moving comprising means for moving said carriage means with reference to said ways.

12. A press as defined in claim 11, wherein said dies have vertical axes and said ways are horizontal.

13. A press as defined in claim 1, wherein each of said dies has a work-receiving cavity whose length exceeds the diameter thereof.

14. A press as defined in claim 12, wherein said ejector means are disposed below said dies and are movable axially of the respective dies.

15. A press as defined in claim 1, wherein said moving means comprise fluid-operated means for moving said grippers with reference to each other and with reference to said dies.

16. A press as defined in claim 1, wherein said frame includes a support for said dies and a pair of columns extending upwardly from said support at both ends of said row, and furthert comprising a feed carried by one of said columns and arranged to deliver a succession of blanks and takeo means carried by the other column and arranged to receive nished Workpieces, one of said grippers being arranged to transfer blanks from said feed to the rst die of said row and another of said grippers being arranged to transfer nished workpieces from the last die of said row to said takeoff means.

17. A press as dened in claim 1, wherein said frame includes a support for said dies and a pair of columns extending upwardly from said support at both ends of said row, said transfer means being located at least partly between said columns and said row including at least three dies, said grippers extending at an angle of substantially 45 degrees with references to said row.

References Cited UNITED STATES PATENTS RICHARD J. HERBST, Primary Examiner U.S. Cl. X.R. 

